skyandtelescope.com • JUNE 2019 49
4526UGC 6887403042164261429343654429444244504517452745354536459646364651466546894698475447534762M49M59 M58M60M61M64M84M85M86M87M88M89M91M98M99M100(^6)
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session at Epsilon Virginis and move
west into the cluster. To fi nd M60, move
5° west-southwest from Epsilon to 5th-
magnitude Rho (ρ) Virginis. M60, with
M59 in the same low-power fi eld of
view, is 1^11 / 3 ° north-northeast of Rho.
Discovered in 1779 by Johann Gott-
fried Koehler, M60 is the third brightest
galaxy in the Virgo Cluster. Studying it
in his 18-inch refl ector, Contributing
Editor Steve Gottlieb described M60
as “very bright, fairly large, [with a]
diffuse halo, slightly elongated approxi-
mately east-west.” M60’s bright core is
certainly detectable in the 10-inch, but
it appears to be surrounded by a circle
of fl uff that thins at the edges but oth-
erwise lacks distinguishing features.
This lackluster description notwith-
standing, the reason M60 gets my favor
is its context: In the eyepiece, M60
looks as if it’s being trailed by a shadow
of itself. That fainter ball of fuzz is
NGC 4647, a spiral galaxy that doesn’t
give up much detail in a scope. It’s just
a more diffuse version of its neighbor.
Deep-sky images make it appear as if
M60 is preparing to get lost in NGC
4647’s spiraling embrace, but there’s lit-
tle evidence to indicate the two galaxies
are interacting, no matter how pretty
a picture they paint. It’s possible some
very early tidal interactions have begun,
but star formation due to mutual dis-
turbance is still in the future tense.
Space-based observations of M60
reveal it to be an elliptical galaxy with
a central supermassive black hole, dark
matter halo, and X-ray halo. Recently, a
team led by Vincenzo Pota (University
of California Observatories) released
a new catalog of the globular clusters
associated with the galaxy — all 431 of
them. The distribution, rotation, and
velocities of the globulars helped lead
the team to the conclusion that M60
formed via a merger between two gas-
poor galaxies, followed by a period of
satellite accretion.
The Virgo Cluster is well-placed for
observation through June from mid-
northern latitudes — if you’re willing
to stay up late, that is. For example, on
June 5th, when the Moon is just two
days old, M60 is comfortably placed
more than halfway up the sky for
observers near latitude 40° north when
true darkness falls near 10:30 p.m.
daylight-saving time. It takes a good
three hours for the galaxy to drop to an
altitude of 20° on that night. Around
June 20th, three nights after full Moon,
M60 stands 10°–11° lower at the end
of astronomical twilight, so descends
to an altitude of 20° in only two hours.
Observers around latitude 30° north
will have longer observing hours (add
an additional hour to the windows for
the dates mentioned above) with the
target higher in the sky, while observers
to the north will have to hustle to do
their galaxy-hopping. At latitude 50°
north, darkness won’t arrive until mid-
night, and even on June 5th, M60 will
only stand 38° high at that time. By the
20th, you’ll have 30 minutes at most to
catch M60 in a dark sky, and that’s only
if you have a very clear horizon and
excellent seeing.
However long you get to spend with
the Virgo Cluster, you’ll fi nd yourself
wanting more. One galaxy inevitably
leads to another, and even if you fi nd
your favorite, the pull toward further
exploration will keep you coming back
to these spring sights even as the calen-
dar invites you to turn toward summer.